C user input only integers, return value from scanf -

i trying user input, , want make sure enter integers, , if don't ask them type again (loop until right).

i have found lot of different approaches this; more complicated others. found approach seems work.

but don't why tested in code:

scanf("%d%c", &num, &term) != 2 

i can understand scanf outputs number of items matched , assigned, don't why outputs 2 if integer.

the code in c is:

int main(void) {     int num;     char term;      if (scanf("%d%c", &num, &term) != 2 || term != '\n')         printf("failure\n");     else         printf("valid integer followed enter key\n"); } 

trying put in loop:

int main(void){  int m, n, dis; char m_check, n_check, dis_check;  do{     m = 0; n = 0; dis = 0;     m_check = ' '; n_check = ' '; dis_check = ' ';  printf("please enter number of rows m in matrix (integer): "); if(scanf("%d%c", &m, &m_check) !=2 || m_check != '\n')         m_check = 'f';  printf("please enter number of columns n in matrix (integer): "); if(scanf("%d%c", &n, &n_check) !=2 || n_check != '\n')             n_check = 'f';  printf("should random numbers come uniform or normal distribution?...  please press 1 uniform or 2 normal: "); if(scanf("%d%c", &dis, &dis_check) !=2 || dis_check != '\n' || dis != 1 || dis !=2)             dis_check = 'f';  }while(m_check == 'f'  || n_check == 'f' || dis_check == 'f'); 

i've tried inputting m = 3, n = 3, dis = 2, , loop starts on , asks me input number of rows. , if when asked press f or start looping crazy on printf-statements :)

entering integer match formatter %d , assign value variable num. %c formatter take newline character ('\n') , store in variable term. scanf returns 2 cause 2 elements correctly assigned (num , term)

if don't enter integer formatter %d won't match correctly, , scanf won't return 2, producing failure

edit: do-while loop goes crazy cause conditions in last scanf wrong (dis != 1 || dis !=2). should be

if(scanf("%d%c", &dis, &dis_check) !=2 || dis_check != '\n' || (dis != 1 && dis !=2))