Question

#include <stdio.h>

int main(){
    int l,m,q,j;
    char option;
    scanf("%d",&q);
    printf("%d\n",q);
    for(j=0;j<q;j++){
        scanf("%c %d %d",&option,&l,&m);
        printf("%c %d %d",option,l,m);
    }
    return 0;
}

Output:

3(Input)
3
C 1 4(Input)

 0 -374066224C 1 4

What is wrong with the above code? It is not giving the expected output.

Answer 1

There is still a newline character in the input stream from the initial scanf() (and subsequent scanf()s): this will be assigned to option and the subsequent int assignments will fail as C is not an int, meaning l and m are uninitialised int variables.

To skip it add a leading space character to the format specifier of the scanf() within the for loop:

scanf(" %c %d %d",&option,&l,&m);
    /* ^ */

The return value of scanf() is the number of successful assignments made: check it to ensure 3 assignments are made.

if (3 == scanf(" %c %d %d",&option,&l,&m))
{
    /* Valid input. */
}