Use as follows
for(int i=0;i<[pop_ln_array count];i++){
NSLog(@"Cumilative array at %d is %@",i,pop_ln_array[i]);
if (i==0){
pop_cum[i]=pop_ln_array[i];
NSLog(@"pop_cum[%d] %@",i,pop_cum[i]);
}
else {
NSLog(@"Pop_cum %@",pop_cum[i-1]);
[pop_ln_array[i]intValue]);
NSInteger first=[pop_ln_array[i-1]intValue], second=[pop_ln_array[i]intValue];
NSInteger sum=first+second;
pop_cum[i]=[NSString stringWithFormat:@"%d",sum];
}
}
You are adding two id
s. Which can not be.
Convert it to integerValue or intValue or any numerical and then add.