U vezi programiranja

Napravio sam program koji bi mi trebao nakon unosenja brojeva ispisivati tablicu i zbroj stupaca i redaka...
On to radi, sad je problem sto pri provjeri da li sam unio broj ili slovo da ispise poruku da on samo radi sa brojevima, a ne slovima...

Program mi izgleda ovako:

code:
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#include <stdio.h>
#include <conio.h>
#include <ctype.h>
#define SIZE 10
int mat[SIZE][SIZE],i,k,j,m,n,suma,suma2;
int main(){
do{
printf("...broj redova: "); scanf("%d",&m);
if (isalnum(m)){
printf("...broj stupaca: ");scanf("%d",&n);
if(isalnum(n)){
for(i=0;i<m;i++)
for(j=0;j<n;j++){
printf("\t[%d][%d]=",i+1,j+1);
scanf("%d",&mat[j]);
}

printf("\nMATRICA je:\n");
for(i=0;i<m;i++){
printf("\n");
for(j=0;j<n;j++) printf("|%4d",mat[j]);
}
printf("\n");

for(i=0;i<m;i++){
for(j=0;j<n;j++){
suma+=mat[j];
}
printf("\n%3d. red= ",i+1);
printf("%4d",suma);
suma=0;
}
printf("\n");

for(i=0;i<n;i++){
for(j=0;j<m;j++){
suma2+=mat[j];
}
k++;
printf("\n%3d. stupac= ",k);
printf("%4d",suma2);
suma2=0;
}
}else{printf("\nGeska!Niste unijeli broj.");}
}else{printf("\nGeska!Niste unijeli broj.");}
}while(1);
}

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Please , help me!!!
Hitno mi treba... Thanks in advance

Potpis

"We haven't the money, so we've got to think." — Ernest Rutherford
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