Online C Programming Test - C Programming Test 3
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- Total number of questions: 20.
- Time allotted: 20 minutes.
- Each question carries 1 mark; there are no negative marks.
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- All the best!
Marks : 2/20
Test Review : View answers and explanation for this test.
#include<stdio.h>
int main()
{
printf("%f\n", log(36.0));
return 0;
}
math.h is a header file in the standard library of C programming language designed for basic mathematical operations.
Declaration syntax: double log(double);
#include<stdio.h>
#define PRINT(i) printf("%d,",i)
int main()
{
int x=2, y=3, z=4;
PRINT(x);
PRINT(y);
PRINT(z);
return 0;
}
The macro PRINT(i) print("%d,", i); prints the given variable value in an integer format.
Step 1: int x=2, y=3, z=4; The variable x, y, z are declared as an integer type and initialized to 2, 3, 4 respectively.
Step 2: PRINT(x); becomes printf("%d,",x). Hence it prints '2'.
Step 3: PRINT(y); becomes printf("%d,",y). Hence it prints '3'.
Step 4: PRINT(z); becomes printf("%d,",z). Hence it prints '4'.
Hence the output of the program is 2, 3, 4.
#include<stdio.h>
int main()
{
int a[3][4] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 };
printf("%u, %u, %u\n", a[0]+1, *(a[0]+1), *(*(a+0)+1));
return 0;
}
char ****k;
int (*ptr)[10];
#include<stdio.h>
int main()
{
int arr[5], i=-1, z;
while(i<5)
arr[i]=++i;
for(i=0; i<5; i++)
printf("%d, ", arr[i]);
return 0;
}
Since C is a compiler dependent language, it may give different outputs at different platforms. We have given the Turbo-C Compiler (under DOS) output.
Please try the above programs in Windows (Turbo-C Compiler) and Linux (GCC Compiler), you will understand the difference better.
#include<stdio.h>
int main()
{
printf("%d, %d, %d", sizeof(3.0f), sizeof('3'), sizeof(3.0));
return 0;
}
Step 1:
printf("%d, %d, %d", sizeof(3.0f), sizeof('3'), sizeof(3.0));
The sizeof function returns the size of the given expression.
sizeof(3.0f) is a floating point constant. The size of float is 4 bytes
sizeof('3') It converts '3' in to ASCII value.. The size of int is 2 bytes
sizeof(3.0) is a double constant. The size of double is 8 bytes
Hence the output of the program is 4,2,8
Note: The above program may produce different output in other platform due to the platform dependency of C compiler.
In Turbo C, 4 2 8. But in GCC, the output will be 4 4 8.
#include<stdio.h>
int main()
{
struct emp
{
char name[20];
float sal;
};
struct emp e[10];
int i;
for(i=0; i<=9; i++)
scanf("%s %f", e[i].name, &e[i].sal);
return 0;
}
At run time it will show an error then program will be terminated.
Sample output: Turbo C (Windows)
c:\>myprogram
Sample
12.123
scanf : floating point formats not linked
Abnormal program termination
#include<stdio.h>
int main()
{
int i;
printf("%d\n", scanf("%d", &i));
return 0;
}
The scanf function returns the number of input is given.
printf("%d\n", scanf("%d", &i)); The scanf function returns the value 1(one).
Therefore, the output of the program is '1'.
#include<stdio.h>
#include<stdlib.h>
int main()
{
unsigned char;
FILE *fp;
fp=fopen("trial", "r");
if(!fp)
{
printf("Unable to open file");
exit(1);
}
fclose(fp);
return 0;
}
This program tries to open the file trial.txt in read mode. If file not exists or unable to read it prints "Unable to open file" and then terminate the program.
If file exists, it simply close the file and then terminates the program.
cmd> sample friday tuesday sunday
/* sample.c */
#include<stdio.h>
int main(int argc, char *argv[])
{
printf("%c", *++argv[2] );
return 0;
}
cmd> sample Good Morning
/* sample.c */
#include<stdio.h>
int main(int argc, char *argv[])
{
printf("%d %s", argc, argv[1]);
return 0;
}
#include<stdio.h>
int main(int argc, char **argv)
{
printf("%d\n", argv[argc]);
return 0;
}
#include<stdio.h>
typedef struct error {int warning, err, exception;} ERROR;
int main()
{
ERROR e;
e.err=1;
printf("%d\n", e.err);
return 0;
}
#include<stdio.h>
int main()
{
const int i=0;
printf("%d\n", i++);
return 0;
}
This program will show an error "Cannot modify a const object".
Step 1: const int i=0; The constant variable 'i' is declared as an integer and initialized with value of '0'(zero).
Step 2: printf("%d\n", i++); Here the variable 'i' is increemented by 1(one). This will create an error "Cannot modify a const object".
Because, we cannot modify a const variable.
strrchr() returns a pointer to the last occurrence of character in a string.
Example:
#include <stdio.h>
#include <string.h>
int main()
{
char str[30] = "12345678910111213";
printf("The last position of '2' is %d.\n",
strrchr(str, '2') - str);
return 0;
}
Output: The last position of '2' is 14.
fwrite() - Unformatted write in to a file.
fscanf() - Formatted read from a file.